Telephone-exchange system.



vJ. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED APB. 12, 1906.

Patented Aug. 2, 1910.

3 SHEETS-SHEET 1.

.wi mesmo' attonwg J. L. WRIGHT. TELEPHONE EXGHANGB SYSTEM.

APPLICATION FILED APB.1`2, 1906.

Patentegi'Aug. 2, 1910.

3 SHEETS-SHEET Z.

J. L.\WRIGHT. TELEPHONE EXCHANGE SYSTEM. APPLIoATIoN FILED APn.12,19oe.

3 SHEETS-SHEET 3.'

Patented Aug. 2, 1910.

witwassen UNITED sTATEs PATENT oEEIoE. y

JOSEPH LANE VVRIGrI-I'I.l yOF \VASHINGTON. DISTRICT OF COLUMBIA,... ASSIGNOE. BYv MESNE ASSIGNMENTS, TO THE NORTH ELECTRIC COMPANY. CF CLEVELAND. OHIO,

A CORPORATION OF OHIO.

TELEPHONE-EXCHANGE SYSTEM.

Specication of Letters Patent.

Patented Aug. 2, 1910.

Application filed April 12, 1906. Serial No. 311,387.

To all whom it may concern.'

Be it. known that l. Jost-:rn Lim: ll'nnurr, a citizen of the United States. resuhng at ll'ashington, in the .District of Columbian' have invented certain new and uset'ul `Imi provements in Telephone-Exchange Sys@` tems, of which the following is a specification, reference being had therein to the accoinpanying drawing.

My invention relates to telephone ex-v for the sending or signal transmitting apparatus used by the operators, in which nothing but push-buttons or their equivalent shall be located on the operators` tables. the main control of .the'circuit shall be by relays, and these together with the signal wheels or circuit-breakers are located in the relay or power room.

The characteristic features of my invention are these: A series of number-wheels having teeth from l to l0 are arranged upon a common shaft, and springs adapted to bear upon the teeth are connected to corresponding push-buttons before the operator. When any number desired has been set-np by `depressing the corresponding buttons, a pair of associated relays are. pulled upV and locked on a battery circuitwhich includes a pair of contacts cont-rolled by a disk or break-wheel rotated synchronously with the number-wheels. and acting to cut ofl' the battery from the locking wires suc-- cessively once in each complete rotation. One of these relays is a guard for the other, so that they must be unlockedvin inverse order, that is the Second one first, in order to produce any ettect. The impulse wires from the push-buttons pass Ithrough back contacts on the No. 2 relay and front con-` tacts on the No. l relay to the tunk or other `wire leading to the switches, Yhich are the subjects of control. Thus, when the second relay isunlocked and lets go this ,circuit 1s complete, and as this occurs at the beginning of a round only, the signal which has been set immediately starts to cut in properly.

' its circuit.

At the end ofthe round the No. 1 relay is cut ot`, and since it breaks the impulse circuit when itvlets go, the entire signaling apparatus at once becomes thereby detached from the switch circuit.

I have illustrated my invention in the accompanying drawings as applied to a coinnion battery system in which the operator plugs into the desired connector trunk, and sets up the switch by means ot' the impulses from her sender. I do not lay any claim to the system. nor broadly to the use ot' numberwheels or push-buttons; my invention relating particularly to the circuit of the sending apparatus, and the method ot controlling the same by the two interlocking relays, which render it possible toavoid any-other means of control except the contacts of the push-buttons thei'nselves. These push-buttons are preferably provided' with latches, and are interlocking. so that the ldepression ot' any one push-button releases any other that may have been previously depressed, but each button remains down until another is actuated. l

My invention and the system referred to with which it nitty be used are illustrated in the accompanying drawings, in which-- Figure 1 is a diagram of a subscriber's lineiof a tru1'1kterminal, and an operators circuit for interconnecting them. l" z is a diag'ain embodying my invention, and includes the operators sending apparatus and Fig. 3 is a dlagram oi' a connector switch with its appnrtct'iauces.- 'lhe three gurcs are all made so they can be put together and .constitute one complete diagrani ot' a system employing my invention.

Referring to the drawings and partictmllarly to Fig 1, A is a subscribers station having the usual subscribers common battery outfit. consisting of transmitter, rc.-

ceiver, switch-hook.' ringer and condenser.A

From this sub-station the line-wires 1 2 extend to the central otlice, where they pass through the contacts of the cut-ottl relay. M: which normally connects them to the linerelay M and ground, respectively. The line relay is connected on the other side to the main batter Y, B, and controls a signal lamp, L, associated with the. answering-Jack- J. The answering-Jacks J are. supposed to be grouped in a convenient nanner, together with their signal lamps, L,1n front of operators, and when any line iscalling 1t 1s intended that it shall be connected through a trunk-jack, J with a trunk-line leading 'to an automatic switch S1 (see Fig. 3'), by

' which the subscriber wanted can be directly reached.

- therewith.V

' rent supplyv direct'irom the "through the choke-coil, z'

In order to interconnect the line and trunk-j acks I provide a p air of plugs, P P',- having-their tips and sleeves respectively connected through the conductors `3-A--5 andV 4-6, these conductors being interrupted for direct currents bythe condensers C. The

answeringfplug P has associated with it a' vnecessary in orderl to energize the cut-off 1n making connection relay M of the line vThe calling' plug which I may call the ,'tip, p, thei ring, iff

and the sleeve, p2, the. ringen thiscasecor responding' to the' ysleeve of thel y'pluf llVhen the4 plug is inserted in a trunkvllack,

J', the tip and ring come into connection respectively with the jack sprngsgj, j,"while the sleeve,';b2, comes into-contact with -a thimble, 7'2, connected through@ resistance,l js, toground. This thimble is for test and also to furnish a circuit .for the 'cord cut-ofi relay R2. There are two relays, R2, R3', associated together for controlling 'the 'connecetion of the operators telephone: The relay,

R3, takes current'through the wires 17 and 18'fwhen the plug P is first inserted in an` swer to ay call', the circuit -B,19, 17 18 vand `ground being then immediately 'closed by the relay, R', ulling up. .Thereupon the relay, RB, immediately pulls up,'the relayR?. which.- also controls it remainingv quiescent.' In lso pulling onto the bridge-Wires 7--8 across the cordffconductors B-fl.` This lsecondary ',L'circuit" contains theiVoperators4 receiver, "l", and the secondary winding, ,of'theinduction coil I.l

The-primary, i', is includedfinfa short-cir-` rcuitl 13;-14' with the condenser; CQ, and.' the v transmltten-.T-,the 'latter deriving its-lcurback contact on the relay, R2, to'the tip conductor' 5 and so to the tip of the calling plu,P. y

T e trunk-lines 23---24y which tenninate in up it closes the two sidesof'fvthe'jacks, J ,are each multipled' to all the v sections of the switchboard, vso' that any operator can reach anyl trunk. ,The trunks are'arranged in groups',l those of'each group leading to similarf'swit'ches in which .the f same group of subscribersflinewires are lnultipled. This, necessary so asto always have enough idle trunks and switches-z.-v to reach a number of subscribers of thesame; y

groupat the same time. Each .connector switch is supposed to contain the 'terminals 'of one hundred lines, andas a 4fair average I may assign ten switches to each `onejhun- I dred lines', so as to be able to call'ten vsubscribers out of thatparticular hundred at the same, time. 'All of these; subscribers and the ten trunks'from the tenswitches are carried together to the' switchboard `"vthere .they are mult-ipled Aand have ther-jacks appe arf together ina. up on all'ythe 'lines are multipled into the ten switches,v

switchboard sections. T ese jacks may be` arranged in acontinuous line eitherv ver.- t-ically or horizontally, preferabl the former,sothatlinltesting to an 1dle trunk, the operator will'simply' run 'the tip of her lug. down,the...rov v-` 1n thep .group4 desired. heseggroupsf'arenumbered from' 0 to 99,

, hicljlvfm eansthat through Athe trunks o f No.

10.group.ithegssubscriberslines,whose numbers l'arefron1m0115o .99, can 'be' reached; through N o;1'ifgroup those whose' numbers are :from

v lto..199,canbe..reached; through-No. 2 grouprthoseiwhosefnumbers are from 200 to' l v`.299. can be-reached,.and so on up 110.9999, or

if it be desired to carry it l so far,evento 99,999, which 'would of course require 10,000m1'1ltiple i -jacks per l section of three operators posi-v tions; which :is the same as in a ,tenthousand multiple-board? now. In 4other words, the same 'multiplelboard which.;now v`'serves .10,000 subscribers can be cut over by present invention without the slightest di culty to accommodate 100,000 subscriber-sat least. so farffasp'regards vthe multiples. In

vactually reconstructingsuch awboa1`d,l it :would be lnecessary in any ycase'f'to increase the number of ,answering-jackgand also of cords plugs since the 4.operators y will ,handle a great many morel` calls than v.at

present, w ich meansthat a' great' many more, lines per position would be required.-

' I.and makingthecon'- l In answering a call nection the operatol proceeds as follows: Seeingl he lamp, L, `lyrlight,she inserts-plug,

.P ,lnto thecorf'esponding jack, J, whereupon the'batteryf'pBs'ends.current at once through ythjefsleevefrelay, It', and the cord-conductor o the line-extensioni25, to the cut-off relay, ,pand ground.` The" cut-off :relay thereontothe'irextensions26 and 25 and thence rela Rzpullsvup and opens the'conductor y lea ing tothqlamp L which had just been 'pon ,pulls up, putting the line-.wires A1-'2y l onto the cord-'conductors 3 and nvihereuponvr vtime asks Number'i Aciosed -by the relay R-, the entire action being too quick for the lamp t0 have time tolight. At the same time, relay, R3, pulls up and the operators set, O, is instantly bridged across the answering-end ofthe cord, while the test-wire 11-12 remains connected to the tip of the calling-plug. The operator picks up this plug and at the-same Ascert-aning the number, she tests with the plug, P; the

trunk-jacks corresponding to the hundreds of the line.wanted,by running thel tip, p,

down the row of thimbles,` i2, until she no longer gets a click. AIt any `trunk is busy,

'having a plug in it, thepotential of its jack thimbles, i2, will beraised by-main battery,- B, through 'thel circuit -19, 2 7, 28 and the relay R2. Hence the tip of the testing plug' .will take current off of this througlrthe conductors 5, 12 and 11 to the testing operators tertiary winding, 2, this producing 'a click lvin the receiver, T', each time'the tip, p,

asses over a charged or busy lthimble. ilavin reached a jack which roduces no click, t e operator puts in the p ug P. Re' lay, R2, instantly pulls up, and the operya-tors telephone is disconnected at once.

This much of the operation is substantially the same as in an manual system, substituting trunk-jacks or line-multiples, of course. The balance of the operation, however, is entirely different. The trunk 'Q8-24 shown in the diagram, leads to the connector switch, S, shown in Fig. 3, yand this switch is operated by means of impulses over the'twosides of the trunk, in a manner which is generally familiar to those acqnainted withv the art. In order to do this need them.

. figure, Q0, Q, Q', Q2, QQQ, Q5, etc., are'.

I provide the operators with impulse transmitters or' senders from ,which the various operators take their impulses as they For convenience I will first describe this arrangement as it is shown in Fig. 2, and will then proceed to point out its effect upon the, apparatus of Fig.' 3. In this a set of wheels` mounted on. and' turning with a common shaft, which may be driven in any suitable manner. The wheel, Q0, puts battery and ground alternately on the. wire 29,,which for purposes of illustration represents the metallic shaft connection between the wheels. The wheel, Q, is' insun' lated `from the'v shaft and is grounded, has

an insulating spot in its periphery, and controls by meansof .this spot the locking and unlockin which willv appear from the statement of operation. The wheels, Q', Q2, Q3, Q4, etc.,l

`are number-wheels, the, lirst one having 'one tooth, the second two teeth v and soon up toten teeth. (For simplicity of illustra'- tion only five wheels are shown). Around these wheels are three sets of pens, connected to the three sets of keys, K', Ivi-3K2. As

wires 30 and 31,A in a manner.

the wheels revolvey from the position in which they are shown in the ligure, they first make cont-act with the upper pens, g', thenwith the ens, q2, then with those, q2. The rst set with their buttons or keys, K,

`transmit the tens digit of any number, the

next set transmit the units digit, and the third set the ringing number for partyline work.v All this wlll appeal' more clearly .from the statement of operation.

The keys, K', K2, K2, are of' the `so-called self-latching selective ringing Vtype now in common use on manuall switchboards, `and employ the principle shown in the patent to Ham, No. 605,09l,gran ted VJune 7, 1898.

When any key is pressed down it pushesback thelatch and releases the one that was previously down, then latchinfr itself. It

will be noted-'that the bank of keys is Vdivided into three sets or rows, Ky K2 and .K3 respectively. Therows are each provided `with the latching device 'of Ham. cited, the

rows being independent of each other in this respect; thustone key and only one of each row will remain depressed, the previously depressed key of each row being released by the depression of any other.` In a bank or row of keys. of this nature, a key is depressedthr'ough a travel carrying it beyond the locking point; upon release it returns 4a very shortdistance and /remains locked there until released by the` depression of the.

next key used. I take advantage of this detail in the row of keys K3 in the following manner: The pairs f springs as 704 are to remain `locked .when thekey is pressed, as described later, but the triple springs la are springs'requiring but a momentary contact to energize primarily the Vpair of locking relays lit-R5, To secure the' desired endjI -so gage the relationaof the springs lo to the push button of the key thatthey are closedy ico other back contact of the same relay.- The numbers to be sent are set up by depressing the keys, one of each row, thekey of row K3 being depressed last, .and the ac t of depressing that key y'serving to energize and lock the relays R4, Ri', and then the signal is started atthe beginning ofa rotationof the shaft, when the irst tooth of each wheel' .is ab'out to strike its pen, (1, by the relay,

izo

R4, being denergized, while the'relay,

remains energized. vThe trick of this is .in the arrangementof ythe spring pens, q, q, on the Wheel, Q.

This wheel is rotated Withgls'fi;

'y the others in the direction of the arrow, and

its insulating `spot passes 'lirst under the'.

spring pen, g5, momentarily cutting ground'.

off of that and the wire 31, then under th"e'L pen, g, taking ground oil'- of that.

In calling the number wanted, which we will assume to be 4432-3, the operator plugs through i'nto ajack of No. 4 4: grou ,then pressesl down'button No.3 of the set, No.2 ofthe y set K2; and No. 3 of the set K3. The buttons. of the sets lK and K2 have their several individuallwires connected to the springs on'- the several individual wheels, Q, Q2, etc. and the effect of pressing downl the .buttons as mentioned is toconnect the pen of the wheel, Q3, through the springs, c of -the buttonJc, tothe wire 32. 'At the Sametime the pen, 2,' of the wheel, Q?, is connected the springs, los, of the buttons, K2, tothe wire 33 and the spring, g3, of wheel Q3, is connectedv through thel springs, 764,

'- the button, 7c?, to the wire 32. The setof buttons, K3, also have what I may callstart ling springs, kf. This set of buttons 'being the last, `or ringing set, the number is ready for transmission' when any one of .them is depressed, hence any one of these buttons' not'l onlyinishes setting up the number, but by closing the springs, lc, puts ground on the starting wires 37- and 38, ,which 'pass to the tw'o relays, R4, R5, respectively, and

g thence throught-he common return wire 39 to battery B and ground. Both the relays I -f pullvup, and lbothlook, the lockinr circuit of the lenga@ being as fonows: e9, R4,

v. Q and ground; Having thus set up the slgnal and put it in, condition to be startedat 'the beginning of a revolution of the main shaft, and'having also plugged into'the'n'ec-` essary hundreds group, the operatorsxwork 'is v'linished She pays no :further attention Pto thefco'nnection until the subscribers have completed their conversation and'have hung plugs.

go, vand-the lamp," L', lights 'to callfbr disi connection.

The signalhaving been set up as described, the apparatus-l of Fig. -2I thenope'rates as follows: The Wheel, Q,in revolving will bring the insulatingspot. under' the pen,

l'at first, and might thereby1 cut olf the reay, i

R, prematurely, but t s is -provided for .by making a branch locking circuit 310 which iscontrolled through a oontact'of the starting relayiRf i v.atl"ecte`d. 'Moreoven it will be observed that ence, as'long as the relay, R, is energized, the relay, R, cannot be the' wires 32 and 33y remain disconnected from the wires 15- 16 until the relay Rt is energized, whileV the relay R4 is' denergized. This condition is brought about when the in- .Qand ground. The locking cirv cuit of 5 is as follows: B, 39, R?, 7'7, 31, g5,"

The operatorthen pulls the' sulating spot reaches the pen, The reuous circuit from wire 32 as follows.: 32,11',

` 34, r3, 16, .5v (in Fig. 1), and to trunk-wire 23.

e also have-,a circuit for wire 33 asv follows: 33, r2., 35, r4, 15, 6. (Fig. 1') and the other trunk-wire 24. The insulating spot soon as the above desired con ition is atset, K', comes .over the wire 32 to the wire through which it passes into `Fig-3 to the relay, R", vwhich will be.- resently described, and which .I shallcall or convenience the vertical motion of the switch,` while'the relay, R", reduces a vrotary `motion-thereof.v

tothethird set of pens, g?, and the battery' limpulses determined by4 the key, ik, then `the vertical relay, R, v After this', the in'- sulating spot ony the Wheel, Q, reaches the already denergizfed, this breaks the locking "35 34 and'leaving the vapparatus free'for another operation.

exchange.

the type shown in the following patents:

321, granted March 13, 1906. The circuits in the -pres'ent case are entirely different from those of these patents, but the mechanical .structu're is so far'the same that I em,- ploy a vertical spindle, s, which. carries wipers, s', to coperate 4with theline-terverticall relay. At the end 'of this group'of" through which they reach the relay,'R7, in

- two-relaysare quite accurate inthis system spring, g5, and momentaril u -Jcuts off theground therefrom. Since t Ve relay, R, is1

circuit .of the relay, R5, and itlets go, disconnecting the wires 15a-16 from'the wires It may be 'stated' here that eachl cord pair is equipped with apair of relays RL- 5 i and a bank of keys K--l 2-' 8- individualf'- to thaty cord pair, but that the commutator.- shaft and its series of Wheels is common 'to all cord pairs and connectors in the entirev .l lay, Rf, .then lets Ago, and we'k have -a continreaches the pen, g", just before-the first tooth.ll on each wheel reaches its pen, ,"hence as tained, thel set of battery impulses whichy has been determined by the key, lo, of the 16 and so enters the wire 23 of f the trunk,

2 will pass fromv ground onto the Wire33l and ,l p

scribed and which `I shall' forfconvenience Atthe en of this second group of impulses v the teeth on the wheels yhave gotten around f come lthrough the wire 32 onto .the wire 16 and so again to the trunk-wire 23 and to,v v

Referring now to Fig. 3, I- will briey dev scribe the switch operation.' The switch, S, "is shown only in diagram, but in so far as its mechanical features are concerned` it is of Keith and Erickson," Nos. 815,176 and 815,- I

minals, s2, (see Fig. l) or line-multiples, in the switch-banks; the switch spindle i", set up step-by-step by the vertical magnet, s,

and is rotated step by step by the rotary f magnet, s1, controlled respectively by the rc- There are supposed to be -e5, which yit opens'when it is down in its normal position of disuse, for restoring purposes, as will presently appear.

pawls from the respective ratches of the spindle, s, allowing the spindle to drop down in the patents referred to. This release magnet is under the control of the relay, R10, which in turn is controlled by the relays, R6 and RT. It is also vunder the control of the test relay, R11, which however isvonly connected at the first instant that the wipers, s', rest on thel desired line-contacts, being thereafter cut off.

R12 is a ringing control relay; R13 is a trunk lcut-oft' relay and R14 isa ringing re-y lay controlled by the commutator, X, whichis common to the entire exchange, and is mounted upon the shaft carrying the wheels Q0 Q, Q etc., of Fig. 2, or is mounted to revolve in synchron'ism with that shaft and its commutator wheels. R15 is a s lou7 lacting relay, preferably a solenoid,- which connects the test relay, R11, at the moment of effecting connection, as controlled by the first ringing impulse, and at the same time opens the generator circuit 40-41, While the proper current isbeing selected.

R1 to R11, inclusive, are selective relays for enabling one or the other of the ring= ing generators, Gr, Gr', Gr2 and G3, to be connected onto the ringing contacts of the ringing relay, R11, the particular generator being determined bythe number of 'mpulses received through the relay, R12, Which operates the relays, R1, R111, etc., in succession,

`each of them locking as it operates.

The operation of this trunk scheme is as follows: 1n ,selecting the number lWehave assumed 4432-3; the trunk itself corresponds to the numl'ier44, so We have first three impulses coming over .the wire 23, to the relay, R, followed by two impulses over the wire 24 to the relay R7 andthen three impulses again over the Wire 23 to the relay R. .The first three impulses coming over the Wire 23 cause the relay' R6 to pull up three times,

each time closing the following circuit: 13,

42, '43. 44, s3, 45,146, 47 and ground to battery. 'The vertical magnet, 83, steps the spindle, s, of the switch up three steps, so that the Wipers, s", stand opposite the thirdrow s is therelease magnet of the sWitch, -which when energized removes the detent magnet s. I with Which the test wiper rests in contact is lnot busy no circuit will exist from that test of contacts.` Two impulses then come over wire 24, aii'ecting the relay R7, which pulls up twice. the iii-st time closing the following circuit: B. 42, 46, R", 49 50, armature of R1". 5l to ground and to battery. The relay. t". instantly prls up, cutting off the vertical magnet. a, and locking itself by the following path: B, 42, 48,-R1, 7", 52, 50, 5l and ground back to battery.v The vertical magnet, s3, is therefore cut off for`the rest of the transmission. The rotary magnet, at, however, gets current each time the relay, R1, isv energized over the following path: B, 42, 43,' 44, 8*, 53, 54, 55 and ground back tobattery, so that the wipers, s', rest on the second pair of contacts in the third row,

or No. 32. rIhr/ee impulses now come over the Wire 23, causing the relay, RG, again to pull up three times. Each time it closes the following local circuit: B, 42, 56, R12, 57, 46, 47 and ground back to battery. As

a branch of this same circuit, the Wirel 5S comes in from battery wire 42 through the solenoid R15 and goes yto 57, 46, 47 and ground. At this ypoint in the development of the connection immediately following the closure of the contacts of relay R@ at the beginning of the first generator-selection impulse, two things occur simultaneously:

(l) The solenoid R15 attracts its core,

opening the Wires 440--41 and closing the switch 62 whereby a test circuit is formed,

through elements B, 42, 62, R11, y63 to upper s', which at this moment is resting in contactvvith the line selected through the R14, contact of R13, conductor 23 and Winding of RG to ground if that line has been called; in either case the test relay R11 will be energized and in turn will energize the release If, however, the selected line Wiper to ground and the test relay R11`wi'll not be energized; a branch path for the conductor 63 exists through the talking conductor of the trunk to the left hand contact of relay R11 and thence to an armature contact of relay R13 where it terminates open, but subsequent to the energization of relay R1* as about to be described, this branch path passes to the inner contact of the left hand armature of that relay and thence over the conductor 41 to the right hand switch of the solenoid R15 vWhich during'the test period is open, and thus ltest relay R11 has its circuit open at all oints and the design of .the device as arwho e is that no energization of that rela;r may result whenthe lineselected is in a condition of disuse and sub ject to use in the connection now being` established.

. (2)` The relay R12 is energized over the path B, 42,56, R12, 57, 46, 47, and ground.

By 'the closu-re of the left hand armature of relay R12, circuit is formed through elements B, 42, 56, armature oiy R12., 60, winding of R13', 61, vswitch 35 and ground, energizing relay R13 which locks itself energized over the circuit B, 42, 43, armature and inner contact of relay R18, winding of relay R18., 61, s1 and ground. This energlzation of trunk-connecting relay R13 connects the conrelay l ductors 23-24 of the trunk through to the outer contacts of the ringing relay R11' and through to the wipers s. This furnishes a path through test relayR11 as follows z-B, 42, 62, R11., 463, talking conductor to left hand armature of R14, back contact and talkingconducto to armature of energized 13, conductor 23, vwinding of relay 1R and ground; however, .this circuit. is adapted to be opened by the attraction of the armatures ofrelay R14 and it is the function of the connector switch that the' opening of this circuit at R1* shall succeed its ,closing at'R b`y a time limit so smglathat.

' restoration of the connector switchii's' not permitted. lit will be` notedin the study.' of this time element that thetest relay R11 must attain the degree :of magnetizationwrequiredyto 'attract its armature,` must swing its armature throu h its full "travel toclose its contact, and tatsubsequently to the closure ofthe contact o.R .11the release magnets"v mustfr'each its yrequired degree of 'magnetization` and must overcome the in'- 'ertla of `its armature and move it through ,4o

some definite are before release of the switch S. willbe eiitedg'this series of necessarily consecutive operations limits the duration of y lthe momentary false test here considered.

The ommutator X, as has been menvt1oned, 1s carried upon the sha-ft which carries the numberwheels and commutator de` vices Q9, Q,'Q, Q2, etc., and the commutator X is adjusted angularly with respect to those wheels so that the conducting portion of X is in electrical connection with its brush at the time that the energization .of relay R1"- occurs. Itis seen therefore that by the `closing of the Vcontacts of i relay R18, by which current `flow through' test .r'elay' R11 was permitted, current flow also was simultaneously provided for.' lthrough the 'path B, 42, X,A winding lof R11, contact and armature r11, 68, 50, r1",

tact, thereby cuttingoi current `from relay R11, in ample time to 4prevent the resteration of the switch S by operation of releaseV magnet s",'the break at the armature of R1* probably occurring in time to prevent any contactwhatever at the armature of relay R11.

winding of relay R6 by` the'break at the armature ofrelay R1, and the design and' Thus a test `condition is maintained, i with the test wiper s isolated from the.

adjustment of the commutator VX shall be such that the relay R11 is held energized throughout themaiimum period occupied by generator-selection impulses and until the opening of the circuit'of the test relay R11 by the opening of the switch 62 up'on release of the armature' of the solenoid 15. 'lhe armature of the solenoid R1l5 is sluggish and does not open the switch 62 bef tween the generator-selectionim ulses, so that 4the test circuit here describe fis maintained continuously during "the period of generator-selection. r Leaving the various parts of apparatus in the condition now considered, we will `follow the" .action of the apparatus in responsev to.

the generator-selection impulses. In the instance assumed, since, station No. 3 is to-be calledthree battery impulses will be received over the wire 23 operating the armature of Vthe relay Re successively three times, which in turn acts over the path 47, 46, 57 R12,

etc., to operate the armaturesof relay R12 in succession three times; the armature r11 through' its front and back contacts effects the selection vof the desired ringing generator as ollowsz' uponattraction ofl 1'12 by the lirstgenerator-selection impulse, it makes electrical connection with its inner contact, j

but inasmuch as the wire 64 is open at the armature of relay R1n'o complete circuit is closed, Upon the release of the armature 1'12'at cessation. of theiirst generator-selection impulse, circuitis closed through` ele-- ments B, 42, 43, contact of'R, 60,'1-'11,-65, Contact of R1", winding of'R1" 'and ground, energizing relay R10 which locks over the circuit B, 42, 43, contact' of' R11, 60,69, armature and contact of R19, Winding ofR1 and` ground.I If but one generatorfselection impulsewere received, the generator G would remain in connection with conductor-,40

pnductor 41 lie 'beginning l ready for connection through to the ringing! relay R14. "Attn of the secon generator-selection impulse, .relay-R11 is energized and armature r `is attracted, closing circuit through 'elements 13.421,43, `contact of R11,`60, r1, 64 .closed ppntact of lower armature of .relay R1?, back contact 'of unenerg'ized relay R20, winding of relayR1a andoround, energizing relay R1 which then loc s over the circuitfB, 42, 43, contact of R18, 60,Y 69, armature contactr and winding of R1". Uponthe cessation of the second generator-selection impulse, the armature correva i112 is released, closing-circuit over B, 42, 43

i would be to leav'e generator G connected to conductor. 40. through cont-act of energized relay R16, that being the proper generator for ri'nging the second station on a party line. At'the beginning of the third and last generator-selection impulse, the armature 7'12 is again attracted, closing-circuit over elements B, 42, 43, contact of R13, 60, 1'12, 64,

closed contact of energized relay R1, closed inner contact of energized relay R20, closed outer contact of unenergized relay R21, winding R1", which' then locks itself by current through its own contact and winding over conductor 69 to ground. Upon the cessation of the third and last generator-selection impulse, the armature 1112 is released, closing circuit through elements B, 42, 43, contact of R13, 60, 1'12. 65, closed inner contacts of energized relays R111 and R1", closed outer Icontact of unenergized relay R11, winding ot relay R21 and ground, energizing relay' R21 which then locks itself by current through its own armature contact and winding from conductor 69 to ground. This leaves relays R1 and R1T energized and leaves relay R18 I -unenergized, thus effecting the connection of generator G2 to the conductor 40, and as the generator-selection impulses now cease, solenoid R15 releases its armature, opening the circuit of the test relay R11 and closing the circuit between conductors 40-41, thus connecting the selected generator Gr2 over conductor 41 to the inner contact.- of the left' hand armature of ringing relay R14 and thus through the upper wiper s and to the line' conductor of the selected line to ring the third station upon the party line selected. The ringing will continue until the insulated portion of the coinmutator .X passes under the brushof that comn'iutator when the circuit of the winding of relay R14 will be interrupted and by release of that relays armature the circuit'from the wipers s willy be removed from the generator and carried to relays R7 and R6 respectively. The line selected will be subjected alternately to periods ofringing when the relay R14 is energized and to periods of non-ringing when the relay R14 is denergized. Upon the answering of the called sub-station, or of any sub-station upon that party line, during a period of non-ringing, current immediately will tic-w through elements B, 42,

of relay R1T and ground, energizing relaywinding of R1, 24, lower s', line conductor, substation bridge, return line' conductor, upper s', 23, winding of R and earth, energizing R and att acting its armatures.

By the operation lof the left hand armature ot' R, circuit is closed through elements B, 4Q, left hand armature and inner contact of R, winding ot' R1", 54, contact and left hand armature of R255 and ground, ener-` gizing-R11 which then. locks over the circuit B, 42, right hand armature andl Contact of R11 to winding of R10, 54, contact and arma-I` ture of RT, and ground. By energizatior of relay R1, ground is taken ott of wire 50] so that ringing relay R14 may not again be` energized. Also by the' energization and locking of R1U the relay R is released and remains released throughout the remainder of the connection. This is theconditionwof conversation and continues until the hanging up ot' the telephone and the breaking of the substation bridge upon the called line.

Upon the hanging up ot' the telephone and the breaking ot' the .substation bridge upon th'el called line, disconnection of the switch S is etfected as follows: Circuit is interrupted over the return wire of the line and through relay R11 to ground, releasing the armatures of relay R, but current continues through elements B, 42 winding Aof R7, 24, lower wiper s', and the sleeve side of the connected line and the winding of its cut-oit relay M to ground, maintaining the energization of the relay R1. By the release of the let't hand armature of relay R a release relay circuit is established through elements B', 42, lett hand armature and outer contact of'deenergized relay R, winding ot' release relay R22. inner contactl and arma ture 1'1" of relay R10, 51 and ground, energizi ing release relay R21 which, by closing its contact, energizes release magnet s, which`v effects immediate restoration of all parts of the switch S to the normal position of disuse.v

A consideration of testA conditions during the process'of the connection is desirable.k When the test wiper or upper 'wiper s', connects with the test conductorof the line, no action is taken either to test for busyoiyto place abusy test upon they lineuntil the wheels Q, Q2, Q3, etc. have iny duecourse of progress begun to, send the generator-selec tion. impulses; at this time, byv the. action o*t the solenoid R15, the selected lineis tested for busy condition, the testing tor-busy being continued throughout the receipt ot the .generator-selection impulsesand the lino being lett'unguarded against connection by other connectors; at the close of the generator-selection impulses the test relay is taken oli' andthe ringing generatorA is substituted.

From. this time a busy'test guard condition is placed upon the test conductor .ot the selected line, being alternately the potential oit the selected ringing generator when thel relay R14 is energized, which is suiiicient to i energize any relay R11 which may test the line during the interval of ringing, and between the intervals' of ringing thefbu'sy test consists of the ground circuit through the relay Rl. If the line thus connected with be tested for llousy by some other connector atten'ipting a connection with it and during the interval of .denergization of ringing relay R, acurrent will iow from the connector then testing to the test conductor ofthe line, thence through the test wiper of the connector of Fig. 3 holding the line, and through back contact of relay R14, front contact of R13, 23, and winding of Ru to ground. This current will be of sufficient strengthl to en'- `ergizethe ltest 4relay R11 of the distant connector atten'ipt-ing to take the line being held,

and' this will effect disconnection of that connector but it will not be of suHicient strength to lenergize the relay R inasmuch as by the energization and subsequent denergization of that relay, the said testing current would also restore the holding connector of Fig. 3

` to its lnormal condition of idleness.

Having thus described my invention what I claim and desire to secure by Letters Patent is :Q-

1.111 a telephone system a 'plurality of lines, automatic switching apparatusfor interconnecting the same, and a controlling apparatus therefor comprising the following"instrumentalities: a power-driven iin-' pulse generator', operators? keys and connec- -tions therefrom tosaid generator such that each key when closed will be supplied with a specific number ofv impulses per cycle of the impulse generator, and means to limit said impulses to one cycle, substantially as described.l

2. ln a telephone system a plurality of lines, automatic'switching apl'iaratusfor inl' terconnecting the same, und a controlling a pparat-u's therefor comprising the following instrumentalities: .an impulse generator, a plurality of operators keys connected to said generator so that each' one operated will derive .a distinctive number of impulses therefrom per cycle, means to connect the keys at the beginning of a cycle to the switches, and means to disconnect the same 'therefrom at the end of a cycle, substantially as described.

3. In a telephone system a plurality of lines, automatic switching'apparatus for in? .terconnectmg the same, and a4 controlling apparatus therefor comprising the-following pulses per cycle of the for the relays passing to the \f supply curr-enty for said electroina netic` tially as described.

means when the keys are actuated, su stanf 4. In a telephone systemna plurality of Q lines, automatic switching apparatus for interconnecting the same,- and a controlling` of operators kcysconnected thereto so as to derive distinctive numbers of impulses therefrom. per. cycle thereof, normally incomplete connections from said keys to the switches, electromagnetic means controlled initially in setting the keys, and thereafter .controlled by the impulse generator in its revolution, to connect the same through the keys to the switches 'at the'beginning 'of 'a cycle only, substantially as described.`

5. ln 'a telephone system a plurality of lines, automatic switching apparatus for in terccnnecting the same, and a controlling apparatus therefor comprising the following instrumentalities: an impulse generator, a

.aplmratus therefor comprising the'following- I 'inst-r1unentalities: an impulse generator, a set set of operators7 keys connected thereto so as to derive numbers of impulses therefrom per.

cycle thereof, normally incomplete connections from said keys to the switches, electromagnctic means controlled 'initially in setting the keys, and thereafter controlled by the impulse generator in its revolution, to connect the same'thi'oughthe' keys t0 then switches at the beginning of a cycle only,

and to disconnect the same from the switches at the end of a cycle, substantially las de-4 scribed.

6. In a telephone systema plurality of lines, automatic switching apparatus for interconnecting the same, and a controlling apparatus therefor comprising the following ii'istrumentalities: an impulse generator, operators selective impulse keys, and a con? trolling relay, with connections such that the keys when actuated will selectV the impulses to be transmitted, and will place,the relay in condition to be controlled by the 'generator, the relay when actuated will connect the. keys for the transmission of the selected im pulses to the switches, and the generator in addition to transmitting` the impulses selected will control the relay to complete the transmitting circuit at the beginning of one of its own cycles, and will disconnect the same at` the 'end of one cycle 'of operation,

substantially as described.

7 In a telephone system a plurality Y, of.

lines, automatic switching apparatus for inl terconnecting the same, and a controlling apparatus therefor comprising the following instrumentalities: an limpulse generator, a

set of operators selective keys, a pair of confy trolling relaysand circuit connections from the relays, and from the relays to the switches, together with controlling circuits generator,

.the generator to the keys, from the keys towhereby said circuit connections will be broken at the end of one1 cycle of operation' of the generator, substantially as described.

8. In a telephone system va plurality of lines, automatic switching apparatus for inn terconneting the same, and a controlling .apparatus therefor comprising the followapparatus, and a pair of interlocking relays,

together with a pair ofLlocking circuits for said relays supplied with current through the generator', one of said relays adapted to connectjand disconnect' the trunk-connections to Vand from the keys, the other relay` actin alternately thereto,"also serving'as a guar relay for its'companion, and the lock-v in circuit having current puton andtaken ofig in proper sequence during the operation of the generator so as to denergize the guard relay first, thereby completing the' trunk connection from the keys, and thereafter at the end of a cycle of operation to deenergize'the-other relay, so as to cut off Vthe trunk connection, substantially as described.v

9. In a telephone system, a plurality of lines, automatic switching apparatus for interconnecting the same;-and a controlling apparatus therefor comprising the following instrumentalities t-commutators; keys; relays; bus conductors connecting said keys and said relays; digit conductors connecting said keys andsaid commutators, said keys being adapted to connect said digitjconductors andsaid busconductors, and said relays being adapted to connect said bus conductors to said automatic switchingl apparatus, substantially as described. i `,l0- In a telephone system, aplurality of lines, automatic switching apparatus for interconnecting the same; and a controlling apparatus therefor comprising the following instrumentalities :-commutators keys; two relays; bus conductors connecting said keys and said relays; digit conductors connecting said keys and'said commutators, said keys being adapted to connect said digit conductors and said bus conductors, one of said relays being adapted when denergizedto connect said bus conductors to said auto- `matic switching apparatus, and the other of said relays being adapted when denergized to disconnect said bus conductors from said automatic switching apparatus substantially as described..

l1. In a telephone system, a plurality of lines, automatic switching. apparatus for interconnecting vthe same; and a controlling apparat-us therefor comprising the following instrumentalities z-commutators ;l keys two relays; bus conductors connecting said keys said keys and said commutatore, said keys being adapted to connect said digit conductors and said bus conductors. one of said relays being'adapted when de'e'nergized to lconnect said bus conductors to said yautomatic switching apparatus. and the other offsaid rela-ys heilig adapted when denergized to disconnect said bus conductors from said automatic switching apparatus; and means for energizing said two relays, substantially-l as described.

'12. .In a telephone system, a plurality of lines, automatic switching apparatus for iiiterconnecting the same; and a controllinlg apparatus therefor comprising the following instrumentalities :-cominutators; keys; two relays; bus conductors connectingl said keys and said relays; digit conductors connecting said keys and said commutators, said keys being adapted to connect said digit conduc-v tors and said bus conductors, one of said relays being adapted when denergized to connect said bus conductors to said automatic switching apparatus, and the otherv of said relays being adapted when denergized to disconnect said bus conductors from said automatic switching apparatus; means.

for energizing said two relaysinitially; and separate means for continuing said energization, substantially as described.

13. In a telephone system, a plurality of lines; automatic switching apparatus for interconnecting the same; and a controlling apparatus .therefor comprising the following instrumentalities :-commntators; keys; two relays; bus conductors connecting said keysV and said relays; digit conductors connecting said keys and said commutators, lsaid Hkeys being adaptedto connect said digit conductors and said'bus conductors, one of said' relaysbeing adapted when-denergized to connect said bus conductors to said automatic switching apparatus, and theothej of said relays being adapted when denergized to disconnect said bus conductors from said ,automatic switching apparatus; meansl forenergizingv said two relays initially; means for continuing the energization of thefirst of said relaysV until thebeginning of a cycle ofy impulses from said commutators through said keys; and means for continuing the energization of said second of said relays until the endV of that cycle of impulses, substantially as described.

14. In a telephone system, a plurality of lines; automatic switching apparatus for interconnecting the same; and a controlling apparatus therefor comprising thefollowing instrumentalities: continuously revolving commutatore; buswires; keys connecting selected ones 0f,.saidcommutatore to said bus wires; and two relays connecting said bus wires to said automatic switching appai E lratus, substantially as described. and said relays; digit conductors connecting instrumentalities:ylcontinuously "revolving commutators; bus wires; keys connecting seterconnectingjtlie same; .an

lected ones of said commutatrs to said: bus wlres; andr two relays/connecting .said bus r e wires to said automatic switching apparatus signals fromi 'saidl si f tomatic selective switchgra pair-of condc l tors' adaptedto be associated therewith; a"

. for

f during .the interval of one cycle of impulses vfrom said commutatorsthrough saidl keys,. lsu'bstal'itially as described. if

t16;*Inl a telephonesys'teni, a" continuously ,driven signal transmitting'.-`- device,y prcduc-ll ing in'4 every cycle the. maximum: of signal impulses retuiredv 'for controlling selectivev swltches, an' having impulse selecting keys .as a" part thereof; a' starting and vstopping devicefassociated withsaid si al trans,-

qmittersand"adaptedlto'produce. rst a stopixngi- `,and 1 second a startingcurrent change m the --inte'rim'` between` succeeding cycles; ofV

al transmitter; any 'austartin relayadapted; to connect'said pair ofl con uctors'to jsaidjsignal transmitter in response. to f -a starting impulse; a l stopping. relay' f'placed in Voperative relationy l to sai '-startin andstoppmgdevi'ce' upon ithe'actiui'- tion o1 c said. starting'relay-and adapted to disconnect said pair of conductors' fromsaid signal' transmitting device inresponse to'v a stop ing current change; andlojcking'means gth ofsai'd relays, substantially as .dei scribed@ .j 17.75In1a telephone system, a continuouslyl driven'si'gnal transmittingfdevice producing in every; cycle', the inaximum of y signal mpulses 's'required Uforncontrolling'selective1 vswitches; impulse selecting keys; i a starting andstoppi'ng impulse deviceassociated with p from said si"l `said signal transmitterand keys and adapted to produce'iirst a stoppingcurrent change and second'. a starting current*y change in the' interim between'isucceedingcycles of signals alla', transmitter and keys; .an n ctive switch-a `pair-of com automaticl se e ductors 'adapted associated therewith 'a 'starting vlrpela'y l.adapted 4to connect' said pair' of conductors. to said signal transmitter 'stopplng relay placed inoperative relation spouse to a stopping current change; lock- `mg means forvboth of f said relays fandmanf` Vually controlled means for connecting said and stopping- I and automatic switching ap aratus Ifor ,interconnecting thesame, toget ler with a conive switching apparatus, a bankof selective combination of. impulses required for any matic switching apparatus, a pairof' conf jductors associated with a portion, of 'the thesame'with the commutator device, afrecommutator device,va second -relay adapted tok disconnect said conductors lfrom the comrelays when the keys are set to select a numyto denergize the 'irs't relay atthe end of a set vup on the keys at any time y impulses will not be transmitted the automatic switching apparatus until thev eration, 'when the impulses will be'received scribed. i y

'in presence of two witnesses.lv l ff JOSEPHLANEJWRIGrI-l'l;v

l- 'Witnessesi AJE;yEl )Mons'ron, Jr., EDWARD-E. Cnrnulnrrs-` .4

to 'said startingandstoppingdevice upon' lthe actuation of said startingrela fand` adapted to disconnect said pair of con u'ctors from said signal transmitting device in re-g starting relay operatively with said starting.

tinuously driven commutator device roduc-4 ing impulses adapted tocontrol sa-i select,

particular 4and definite voperatlon of I'the lauto-y automatic switching apparatus to connect lay adapted to connect said yconductors to said cycle of'operation,` whereby a signal 'may 'be` beginning of the ynextregular cycle of op-f l5o; inyresponse.- to a vstarting current change; a

substantially as de-v l l18. In a telephone s ystem,`line circuits l keys for selecting fromsaid commutator" the I mutator, meansV for energizing both of said.

Aber, and means associated with the commutator Vdevice'to d'energize the second relay at e the beginning oi a cyclejoiA operation, 'and ut signa thereby to.

in" 'orderly sequence, Substantially *as de' '1' j I n testimony whereof I aflix lmy signature l 

